Digital television signals replaced analog TV signals in 2009. All televisions built after March 2007 can receive DTV. If you have a pre-March 2007 TV, you will need to buy a new TV set or an adapter that will translate digital signals into analog.
This is the "i" you'll see in "1080i" on LCD TV descriptions. Abbreviated 480i, 720i or 1080i, interlace scan means that a LCD TV lights half of the lines on the screen in one pass and the other half on the next pass. Interlace LCD TVs show less blur in moving images by scanning twice as often, but they actually only project about 30 complete frames per second.
Liquid crystal displays (LCDs) are used inLCD TVs to create color. The liquid crystals in each cell on the TV screen are charged with electricity, which changes the way that light passes through them. A fluorescent light bulb shines light through the crystals, which change color to generate video on the LCD TV screen.
TFT stands for "thin film transistor." In LCD TVs, these transistors are so tiny that they are included in the pixels themselves, allowing pixels to talk to each other. So, an LCD TV listed as a TFT display is better able to deal with fast-moving video with lots of action, such as sports or action movies.
These are individual points of color making up a TV picture. Pixel-count determines a LCD TV's resolution, described as the number of pixels forming the picture. LCD TVs will advertise the resolution as either the horizontal by vertical pixels, such as "1920 x 1080," or as the number of horizontal lines displayed (480, 720 or 1080). The number of pixels on LCD TVs continues to grow as HDTV manufacturers push for better detail.
Abbreviated 480p, 720p or 1080p, progressive scan LCD TVs light every line in one scan. Progressive scan LCD TVs show greater detail by using every pixel each time the screen refreshes, which can be anywhere from 60 to 240 times a second.
Dynamic Contrast Ratio
The difference between the brightest whites and darkest blacks a TV can show. e.g. 1,000,000:1
Plasma Screen TVs
Plasma Screen Television Brightness
The brightness of a is often touted as one of its greatest selling points. Technically, brightness in televisions is often discussed using the term “contrast ratio”. The contrast ratio is a measure of a television's ability to display very bright objects and very dark objects simultaneously. Plasma screen televisions are able to display very high contrast ratios at uniform amounts of brightest, creating a very detailed picture that is not overly garish. Normal CRT televisions often loose brightness with age, or produce images with varying levels of brightness, with darkening at the edges, and overly bright “hot spots” near the center.
Plasma Screen Television Burn In
One term used when talking about the durability of plasma screen televisions is “burn in”. “Burn in” is a term that refers to an etching of the phosphors on the television screen that occurs when a single image is displayed for too long. If a single unchanging image is on the screen for a long time, the same phosphors are heated again and again, causing some of them to permanently retain the image. This burn in leaves a ghost image on the screen – the old image will still be faintly visible even if you change the channel. Almost all televisions, except for LCD screensare susceptible to burn in, but the condition can easily be avoided with proper use.
Plasma Screen Television Size
The size of a plasma screen television is usually expressed with two kinds of measurement: screen size and depth. The screen size of a television is the diagonal width of its screen. Plasma screen televisions range in size from around 30 inches to over 60 inches in width. The depth of the television refers to the thickness of the actual unit. Plasma screen televisions can be up to 4 inches deep.
Plasma Screen Television viewing angles
Plasma screen televisions are lauded for their wide viewing angles. The viewing angle of the television screen is angular range in which the picture of the screen can be comfortably viewed without distortion or loss of brightness. In order to understand what viewing angle actually is, think of the center of the television screen as the center of a circle. The viewing angle radiates outward from the center of the television, left and right, up and down, forming a cone. Within this cone, the televisions picture can be comfortably viewed. Plasma screen televisions usually have a viewing angle of 160 degrees, which means that viewers can almost stand directly beside the screen and still be able to see a perfectly clear image.
How Plasma Screen Televisions Work
Plasma screen televisions operate by illuminating individual cells of color. The cells are actually small containers of neon xenon gas trapped between thin panes of glass, and are grouped in triads of red, blue, and green cells. Each triad of cells makes up one pixel, or dot of color, on the television screen. When electricity is applied to one of the cells, the gas inside turns to plasma, emitting a burst of ultraviolet light. This light then strikes a colored phosphor on the glass, producing a single colored dot. These dots coordinate together to form a single color image.
Plasma Screen Television Aspect Ratio
Aspect ratio is a term used to describe the proportional relationship between the width and height of a screen. There are two primary aspect ratios used in display. Movie theatres, DVDs, and HDTV signals use the 16:9 aspect ratio, also known as “wide screen” or “cinematic” display. Standard CRT television, satellite and cabletelevisio signals, and VHS use a 4:3 or “full screen” aspect ratio. These differences cause some viewing difficulties. 16:9 images shown on a 4:3 screen often use black bars on the top and bottom of the image to compensate for the difference in image proportion. Plasma screen televisions are by default capable of displaying 16:9 images, and can display 4:3 images with minimal distortion.
Plasma Screen Televisions: HDTV ready vs. HDTV compatible
When buying a plasma screen television, you may see that some sets are labeled as “HDTV Ready” while others are labeled as “HDTV Compatible”. The two phrases sound the same, but they mean very different things. HDTV ready sets are essentially just plasma screen televisions that are capable of displaying HDTV media. In order to display the media, you have to buy a HDTV receiver or a DVD player. HDTV compatible sets, sometimes called integrated HDTV sets have their own built in tuner for DTV signals. While this may seem like a cost saving feature, it actually reduces the flexibility of your television, because if standards change then you must replace your entire television rather than buy a new tuner.
CRTs and plasma screen televisions
The traditional television set is known as a cathode ray tube, or CRT. Unlike plasma screen televisions, CRT tube televisions use a beam of electrons to illuminate phosphors to form a picture. The electron beam excites the atoms of phosphor on the screen, causing a picture to form. The beam of electrons must constantly scan the screen to refresh it, producing scan lines. A CRT can produce excellent images, but it suffers from size constraints – the larger a CRT screen, the larger and deeper the tube itself has to be. This means that very large CRT screens can end up taking up undue amounts of space.
A circuit board that is the power supply for the lamp. The ballast creates two different voltages that make the lamp light and stay on. The ballast creates a startup voltage to strike the lamp at 15,000 volts. The ballast also creates the run voltage that keeps the lamp on at around 320 volts.
A color wheel is a device that 6 or 7 colored segments in the shape of a wheel connected to a motor that spin at speeds of 7,200 rpm up to 10,800 rpm. These segments pass and block certain colors when light is shined through them. The operation of this part is crucial the operation of a DLP TV. A color wheel helps to create the color in the picture.
(Digital Micromirror Device) This is an amazing chip that is made of millions of micro-mirrors that are synchronized to move at precise angles to create the picture you see on the screen.
This is a circuit board that connects to the DMD and together create the picture that you see on the screen.
The lamp for a TV is a sophisticated high pressure mercury vapor lamp. These lamps are made to run at high temperatures for extended periods of time. Osram and Philips are the two major OEM manufacturers of lamps. Both brands rate their lamps at 6,000 hours of life.
Lamp Door or Lamp Cover
his a door or cover that lamp sits behind. You have to remove this door to take the lamp out and replace it. This door has to replaced and secured before plugging TV back into the outlet and trying to turn back on.
(Light Emitting Diode) In reference to this guide, they are the lights that are on the front of the TV that flash in certain orders which are codes for service.
Light Engine or Optical Block
This is the part of the TV that processes information and projects the picture that you see on the screen.
This is a part of the light engine in DLP TVs that focuses the light from lamp after the color wheel at the DMD. A light tunnel is 4 pieces of highly reflective glass that are adhered together in the shape of a tunnel.
Original Equipment Manufacturer) This means that the product is made by the original manufacturer and not a copy or replica by another company.
A circuit board that takes incoming AC voltage from the outlet and turns it into various DC voltages that are needed to run the components of the TV.
Signal Processing Board
A circuit board that is designed to take the inputs from the TV and process it into the picture you see on the screen.